A project to advance the state of the art in automated differential leukocyte counting is proposed. The project will be both a continuation and major expansion of our previous work in which 17 leukocyte classes were differentiated in peripheral blood smears using two wide band color separation negatives, and for which a data base of over 1000 cells was assembled. As before, slide scanning rather than "flow" techniques will be used. We propose (1) to record a new and larger file or data base consisting of more than 8000 cells uniformly distributed over 38 different types, each cell recorded directly by a TV microscope system; (2) to investigate combination gradient/threshold and other new boundary finding methods; (3) to perform and record results of scene segmentation and parameter extraction for all of these cells; (4) to investigate new nuclear shape parameters to separate neutrophils (polys) from bands; (5) to investigate testure parameters for differentiating basophils and for measuring toxicity (granules); (6) to determine the effects of spectral bandwidth on color parameter discriminating power; (7) to test our overall analysis and classification system against a statistically developed standard; and (8) to extend our methodology including sample preparation, to the analysis of bone marrow smears.